Isaev N K, Stelmashook E V, Alexandrova O P, Andreeva N A, Polyakova I A, Victorov I V, Zorov D B
A.N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Russia.
FEBS Lett. 1998 Aug 28;434(1-2):188-92. doi: 10.1016/s0014-5793(98)00979-x.
Rhodamine 123 staining, light and electron microscopy were used to evaluate the ultrastructural and functional state of cultured cerebellar granule cells after short treatment with the solution where NaCl was substituted by sucrose (sucrose balance salt medium, SBSM). Cell exposure to SBSM for 20 min resulted in the fact that mitochondria in the neurons lost their ability to sequester rhodamine 123. This effect could be prevented by: (i) non-competitive N-methyl-D-aspartate (NMDA) receptor channel blocker, 10(-5) M MK-801; (ii) a competitive specific antagonist of NMDA glutamate receptors, 0.25 x 10(-3) M D,L-2-amino-7-phosphonoheptanoate (APH); (iii) 10(-3) M cobalt chloride; (iv) removal of Ca2+ from the medium. Low Na+ in the Ca2+-containing medium caused considerable mitochondrial swelling in granule cells. However, the same treatment in the absence of calcium ions in the medium abolished the deleterious effect of SBSM on the neuronal mitochondrial structure and functions. It is suggested that (i) the exposure of cultured cerebellar granule cells to SBSM leads to a release of endogenous glutamate from cells; (ii) Ca2+ ions potentially de-energizing neuronal mitochondria enter the neuron preferentially through the NMDA channels rather than through the Na+/Ca2+ exchanger; (iii) mitochondrial swelling in granule cells is highly Ca2+-dependent; (iv) cellular overload with sodium ions can activate mitochondrial Na+/Ca2+ exchanger and thus prevent permeability transition pore opening in mitochondria.
使用罗丹明123染色、光镜和电镜来评估培养的小脑颗粒细胞在用蔗糖替代氯化钠的溶液（蔗糖平衡盐培养基，SBSM）短期处理后的超微结构和功能状态。将细胞暴露于SBSM 20分钟导致神经元中的线粒体失去摄取罗丹明123的能力。这种效应可通过以下方法预防：（i）非竞争性N-甲基-D-天冬氨酸（NMDA）受体通道阻滞剂，10⁻⁵ M MK-801；（ii）NMDA谷氨酸受体的竞争性特异性拮抗剂，0.25×10⁻³ M D，L-2-氨基-7-膦酰庚酸（APH）；（iii）10⁻³ M氯化钴；（iv）从培养基中去除Ca²⁺。含Ca²⁺培养基中的低Na⁺导致颗粒细胞中线粒体大量肿胀。然而，在培养基中不存在钙离子的情况下进行相同处理可消除SBSM对神经元线粒体结构和功能的有害影响。有人提出：（i）培养的小脑颗粒细胞暴露于SBSM会导致细胞内源性谷氨酸释放；（ii）可能使神经元线粒体去能的Ca²⁺离子优先通过NMDA通道而非通过Na⁺/Ca²⁺交换器进入神经元；（iii）颗粒细胞中的线粒体肿胀高度依赖Ca²⁺；（iv）细胞内钠离子过载可激活线粒体Na⁺/Ca²⁺交换器，从而防止线粒体通透性转换孔开放。
